Hollow shell baseball bats are known to be constructed of various materials, for example various metals and alloys as well as composite mixtures of fibers supported within a resin. Regardless of the material used, striking a ball with the hollow shell baseball bat results in some resilient deformation of the hollow shell together with a subsequent rebounding of the shell which enhances hitting performance. Providing a shell which undergoes more flex and deformation can increase hitting performance of the bat, but tends to reduce the longevity of the bat due to the additional stress imposed upon the material of the bat during larger impact deformations.
In some instance, it is known to resiliently suspend a dampening core within the striking barrel portion of the hollow shell of a bat in an attempt to further improve upon the performance enhancing rebounding effect. The following documents disclose various examples of a dampening core resiliently suspended within a hollow shell of a bat.
CA 2,333,825 by Fritzke et al discloses a bat having a dampening core which spans the entire striking portion and which is separated from the shell by only a very thin layer of resilient material so as to affect the rebounding performance even when the shell undergoes small deformations. The core spans the full length of the striking portion so as to position the core by longitudinally restricting the core within the striking portion.
U.S. Pat. No. 6,663,517 by Buiatti et al discloses about having a dampening core in which the core spans the full length of the striking portion also as a requirement for positioning the core longitudinally within the striking portion. The resilient layer between the core and the shell is again very small such that the rebounding performance is affected even when the shell undergoes small deformations.
Similarly, U.S. Pat. No. 6,398,675 by Eggiman et al provides a core which spans the full length of the striking portion to longitudinally restrict the core relative to the striking portion. The resilient layer between the core and the shell of the bat is again very small so as to affect rebounding performance even for small deformations.
U.S. Pat. No. 5,511,777 by McNeely discloses a baseball bat with a rebounding core which must extend the full length of the striking portion to longitudinally position the core relative to the bat. The resilient layer which suspends the core relative to the shell of the bat is under great compression so as to be reduced by up to 70% of its relaxed state volume with the intention of affecting rebounding performance even for small deformations.
U.S. Pat. No. 9,005,056 by Pegnatori discloses a core resiliently suspended within the shell of a bat by various means. Typically the core spans substantially the full length of the striking portion to assist in positioning the core relative to the shell of the bat. Typically a complex mechanical structure is required to resiliently suspend the core relative to the shell which is costly and unreliable in use.
In each instance in the prior art, the core is required to be of considerable length to assist in positioning the core relative to the shell, however, the core is typically unnecessarily long resulting in an undesirable weight distribution within the bat. Reducing the length of the core according to the teachings of the prior art results in unsolved problems as to how to adequately secure the core relative to the shell. Typical adhesives which are suitable for bonding to common materials used to form the shell of bats, for example metal and composite barrels, tend to migrate into typical resilient materials for resiliently suspending the core relative to the shell, which in turn affects the long-term performance of the resilient material. The unitary resilient layer found in the typical prior art examples for supporting the core relative to the shell is thus considerably limited in the type of material which can be used to avoid problems associated with adhesive bonding to the shell as a means of securing the core relative to the shell.